Presentation on theme: "Corn (Zea mays L.) Leaf Angle and Emergence as Affected by Seed Orientation at Planting Guilherme Torres, Jacob Vossenkemper, William Raun, John Solie."— Presentation transcript:
Corn (Zea mays L.) Leaf Angle and Emergence as Affected by Seed Orientation at Planting Guilherme Torres, Jacob Vossenkemper, William Raun, John Solie and Randy Taylor Department of Plant and Soil Sciences Department of Biosystems and Agricultural Engineering Oklahoma State University
Introduction Increasing Yield Plant population (Cox 2001). o 80,000 and 116,000 plants/ha Reducing row spacing (Lutz et al. 1971). o 40, 30, and 15 inches Leaf architectures of modern corn hybrids (Stewart et al. 2003).
Rationale Stinson and Moss (1960) o When soil moisture and nutrients are satisfactory light can be the primary ecological factor limiting grain yields. Peters (1961) o Systematic orientation of corn leaves using seed planting techniques provides means for capturing more sunlight and more efficient soil shading. Donald (1963) o Leaf geometry and its effects on light distribution with crop and levels of photosynthesis offer potential strategies for improving production efficiency. Stewart et al. (2003) o Leaf architecture of modern corn hybrids can optimize light interception to increase grain yield.
Rationale cont. More homogenous corn stands have 1. Less interplant competition, increased light interception, reduced weed pressure, (quicker canopy closure). 2. Ability to potentially increase seeding rates while substantially increasing corn grain yields. 3. Reduce seeding rates and maintain grain yields.
Light Interception Pendlenton et al. (1967) o 35 % yield increase in corn when aluminum reflectors were used to provide additional light to the middle and lower leaves Reichert et al. (1958) and Stinson and Moss (1960) o Reductions in grain yield when artificial shading was used to reduce available light Sujatha et al. (2004) o Found that in irrigated production systems, prostate leaf architectures from the corn hybrids could assist in integrated weed management with the potential to decrease herbicide rates.
Emergence Hodgen et al. (2007) o Found that if corn plants are delayed by as little as four days, the yield depression of that individual delayed plant was as much as 15 percent. Daft et al. (2008) o Heterogeneous corn plant stands can lead to over application of fertilizers, pesticides and supplemental irrigation because these late emerging plants compete for nutrients, and produce little to no yield. Martin et al. (2005) o Homogenous corn plant stands and emergence may decrease plant-to-plant variation and could lead to increased grain yields.
Objective Identify which seed placement and arrangement could result in plant architecture with leaves orientated perpendicularly to the row and understand the effect of seed position on emergence. With-row Leaf orientation Across-row Leaf orientation
Greenhouse Trials Materials and Methods Planted 2.5 cm deep Medium flats 10 seeds per treatment Redi-earth Adobe Illustrator CS4 software Emergence Leaf angle Analysis of variance Frequency distribution Angle ranges (%)
Leaf angle Deviation from the corn row Between 0° and 90° Angle ranges o 0 ° to 30 ° (with-row) o 30 ° to 60 ° o 60 ° to 90 ° (across-row) Leaf symmetry
Experiment #3 (E3) 5 Dekalb hybrids o DKC6122RR2 o DKC6172RR2 o DKC6346RR2 o DKC6342VT3 o DKC6169VT3 8 treatments 4 leaf stage 400 seeds
Results (E1) Source of variationdfLeaf AngleEmergence Frequency distribution Replication9**NS Treatment5** plants with leaf angle between 0° and 30° degrees plants with leaf angle between 60° and 90° degrees MSE Treatment meansNMean Standard deviation Mean Standard deviation Degrees% SED C.V.367
Results (E2) Source of variationdfLeaf AngleEmergence Frequency distribution Replication9NS** Treatment12** plants with leaf angle between 0° and 30° degrees plants with leaf angle between 60° and 90° degrees MSE Treatment meansNMean Standard deviation Mean Standard deviation Degrees% RANDOM SED C.V.395
Results (E3) Source of variationdfLeaf AngleEmergence Frequency distribution Replication9NS Treatment7** Hybrid4*** plants with leaf angle between 0° and 30° degrees plants with leaf angle between 60° and 90° degrees MSE Treatment meansNMean Standard deviation Mean Standard deviation Degrees% RANDOM SED C.V.337
Discussion Fortin and Pierce (1996) o Found that random orientation of seed resulted in random ear leaf azimuths Bowers and Hayden (1972) o Flat orientation (hypocotyl up) consistently had better emergence (beans) Patten and Van Doren Jr. (1970) o Proximal end of the seed down resulted in earlier more complete emergence with more seedling growth
Field Trial – Materials and Methods RCBD Row Orientation: North-South Row spacing: 30 inches Light interception, V10 and R1 o (LI-1400) Grain yield at harvest Corn Hybrids o Prostate leaf pattern - P0902HR o Upright leaf pattern - P1173HR (within incomplete factorial arrangement) Seed Orientation o Upright, caryopsis pointed down, parallel to the row o Laying flat, embryo up, caryopsis pointed perpendicular to the row o Random Plant Population (in thousands of seeds / acre o Irrigated trial – 20, 30 and 40 o Dry land trial -15, 20 and 25 Row orientation
Objective Development of innovative crop management to improve/maintain yields (reduce pesticides and fertilizer rates). 2 fixed seed orientations and random 3 populations 2 corn hybrids (differing leaf structure) o Prostrate and erect Dry-land and irrigated conditions Light interception Grain yield
Discussion Toler et al. (1999) o Differences in light interception between leaf orientations decrease with maturity. o No differences were found in plant population. o Across row -10% to 20 % higher corn yields than the random and with-row leaf orientation. Sujatha et al. (2004) o 50% less light reached the ground between rows of horizontal leaf hybrid compared with upright leaf in both years.
Conclusions Placement and arrangement of corn seed can influence rate of emergence and leaf orientation. At V10 fixed seed planting intercept more light than random seed planting. At R1upright seed position intercept more light than random. Effect of seed orientation on light interception was independent of plant population and hybrid. Difference in light interception decreases with maturity. Controlled leaf geometry could facilitate planting higher populations with the potential for increasing grain yield or permit the preservation of yields with reduced plant populations.